storing values in a loop

I have a function of the following and it only gives the last value. I want to see a vector of Nf and pf. I tried inserting i. For example Nf(i)=Nf and received the following error:

Attempted to access Nf(2); index out of bounds because numel(Nf)=1.

Error in probabilitycounter (line 23) Nf(i)=Nf

Here is what I have written to produce actual data:

function [Nf,pf]= probabilitycounter(N,mu_x,mu_y,sig_x,sig_y)

%Starting value of Nf
Nf=0;

%Creating a loop to generate pf and Nf
for i=1:N

%Random variable declaration for ux and uy
u_x=rand(1,1);
u_y=rand(1,1);

%Normal Inverse
x=norminv(u_x,mu_x,sig_x)
y=norminv(u_y,mu_y,sig_y)

%Starting Nf and pf Calculation
    if (x-y>0)
        Nf=Nf+1;
    else
        Nf=Nf;
    end
    pf=Nf/N;
end

[Matt J]

Please show us your actual code. There is no statement Nf(i)=Nf at line 23 of what you posted.

[Melissa]

function [Nf,pf]= probabilitycounter(N,mu_x,mu_y,sig_x,sig_y)

%Starting value of Nf
Nf=0;

%Creating a loop to generate pf and Nf
for i=1:N

%Random variable declaration for ux and uy
u_x=rand(1,1);
u_y=rand(1,1);

%Normal Inverse
x=norminv(u_x,mu_x,sig_x)
y=norminv(u_y,mu_y,sig_y)

%Starting Nf and pf Calculation
    if (x-y<0)
        Nf(i)=Nf+1;
    else
        Nf(i)=Nf;
    end
    pf(i)=Nf(i)/N;
end

[John Petersen]

These lines look like problematic

    Nf(i) = Nf+1;  
    Nf(i) = Nf;

Maybe you want to index the Nf on both sides?

Answer 1

[Matt J]

I'm guessing this might be what you want:

 function [Nf,pf]= probabilitycounter(N,mu_x,mu_y,sig_x,sig_y)
  %Starting value of Nf
  Nf=zeros(1,N);
  %Creating a loop to generate pf and Nf
  for i=2:N
  %Random variable declaration for ux and uy
  u_x=rand(1,1);
  u_y=rand(1,1);
  %Normal Inverse
  x=norminv(u_x,mu_x,sig_x)
  y=norminv(u_y,mu_y,sig_y)
  %Starting Nf and pf Calculation
      if (x-y<0)
          Nf(i)=Nf(i-1)+1;
      else
          Nf(i)=Nf(i-1);
      end
      pf(i)=Nf(i)/N;
  end

[Melissa]

Ah so the dimensions were wrong thats why you used the zeros matrix? then had to reset the index? thank you that is exactly what I needed. I really appreciate your help :)